Macule: Definition, Causes, and Characteristics

Definition

A macule is a flat, non-palpable circumscribed area of skin color change ≤1 cm in diameter. It represents altered pigmentation or vascularity without elevation or depression.

Key Features

• Cannot be felt on palpation (vs. papule, plaque).
• Colors: brown (melanin), red (vascular), white (hypopigmentation), blue (dermal melanin).
• Sharp or indistinct borders.

Common Causes

• Hyperpigmentation: Freckles (ephelides), solar lentigines, melasma, post-inflammatory hyperpigmentation (PIH).
• Vascular: Petechiae (tiny hemorrhages), angiomas, port-wine stain (capillary malformation).
• Infectious: Roseola, measles, rubella, viral exanthems.
• Drug eruptions: Maculopapular rash (starts as macules).
• Congenital: Café-au-lait spots, Mongolian spots.
• Inflammatory: Early lesions of many dermatoses.

Diagnostic Approach

• History: onset, evolution, medications, exposures.
• Dermoscopy: distinguishes pigment vs. vascular.
• Biopsy if uncertain or concerning features (ABCDE for melanoma).

Macules are a morphological description — not a diagnosis. Context determines significance.